I know all about this. That's why I just spent $59 on a complete replacement carriage with installed bearings to fix my N1.
https://forum.raise3d.com/viewtopic.php?f=17&t=20199Now that said, we can also have a debate. The N series when first released, there were 2 styles of central crossing block. Cast- just like your pictures, and CNC machined.
Both used the same retention method, both had the same repair problem, but at least in my instance, there was greater slop around the bearing to crossing block slop or backlash in my CNC version. In other words, because of tolerance stackup, the bearings fit very loosely into the housing allowing for slight rock and or backlash on my N1. So replacing the central block because of a bearing failure actually is an upgrade for me- hence while I was annoyed at the cost, in the bigger picture, now near 4 years old on that printer, this isn't a huge operational cost.
Again, some early N series, depending on batch produced, they had to outsource a CNC copy of the original cast central crossing blocks. In my experience and conversations with others at the time, the CNC blocks being a copy had greater bore sizes for the bearings resulting in slight slop. I think (speculation) it was just a one time batch where cast blocks were not available and a short run of CNC blocks was made, and somehow, someone got a detail wrong.